Automatic feed control system

ABSTRACT

Excess feed pressure provided by the system raises a portion of the drilling machine from the ground and causes a sliding movement of a jack leg within a machine support frame. With jack leg movement, a sensor valve plunger closes on the frame, and the sensor valve controlled by the frame-engaging plunger in turn actuates a valve in the pressured fluid feed line to shunt the feed away from the feed motor. Excess feed pressure, capable of tilting the machine - to the jeopardy of the machine and its operator - is automatically attentuated in immediate response to a feed-reactive displacement of the machine.

United States Patent 1191 1111 3,734,202 Gyongyosi {4 May 22, 1973 1541 AUTOMATIC FEED CONTROL 2,711,880 6/1955 McKenzie ..173/4 SYSTEM 3,397,915 8/1968 Small =1 al.... ..299 1 2,894,723 71959 G f ..l7 [76] Inventor: Laszlo Gyongyosi, 137 Grove Ave- I um Son 3/ X clarksburg Va 26301 Primary Examiner-Ernest R. Purser [22] Filed; Man 2 7 Attorney-Frank S. Troidl et al.

Appl. No.: 171,268

Related US. Application Data 57 ABSTRACT Excess feed pressure provided by the system raises a [63] continuatiommpan of Ser No 63 524 Aug 13 portion of the drilling machine from the ground and 1970 abandoned causes a sl1d1ng movement of a jack leg within a machine support frame. With jack leg movement, a [52] U s C] 173/4 91/419 173/37 sensor valve plunger closes on the frame, and the sen- [51] 5 c 5/11 sor valve controlled by the frame-engaging plunger in [58] i 173/4 turn actuates a valve in the pressured fluid feed line to 299/1 shunt the feed away from the feed motor. Excess feed 1 pressure, capable of tilting the machine to the jeopardy of the machine and its operator is auto- [56] References Cited matically attentuated in immediate response to a feed- NI D STATES PATENTS reactive displacement of the machine.

3,648,783 3/1972 Lackey ..173/4 25 Claims, 4 Drawing Fl ures sea 1* 54' 24 3o 22 "Q FEED MOTOR T INDICATOR 74 INDICATOR 64 32 SHUTTL VALVE PNENTEL 3,734,202

SHEET 1 OF 2 740 INDICATOR 74 INDICATOR FIG INV'ENTOR LASZLO GYO/VGYOS/ AGENT This is a continuation-in-part of my co-pending patent application, Ser. No.63,524; filed Aug. 13, 1970; titled Feed Control System, and now abandoned.

This invention pertains to feed control systems for hydraulically or pneumatically operated drilling machines of the type which are supported by jack legs usually leveling jacks while in operation, and in particular to such a system which automatically limits feed force to the highest practical value. As the drill bit of such machines is being rotated, the main purpose, of course, is to exert a feed force against the ground through the drill string to the bit. This invention, then, provides a feed force which is continuously as high as possible, with minimum variation in is intensity, to result in the best penetration of the drilling bit while avoiding the danger of over-tilting or accidental tipover of the machine.

With feed control systems known in the prior art, ei-

ther one of two approaches have been adopted, for

feed force control, to avoid over-tilt or tip-over of the machine due to excessive feed. These two are:

1. The feed force capacity of the equipment is artificially limited, on a conservative level below the actual capacity, resulting in a sacrifice of efficiency for safety. The safety margin built in allows for variable conditions, such as: weight reduction of the machine, as drill rods are being transferred to the drill string; variable wind conditions; inaccurate leveling of the machine; etc.

2. The feed force capacity of the equipment exceeds all site operation requirements. In this case the operator must be the controlling element; the dangers of over-tilt or tip-over are governed solely by his human judgement in cautiously delimiting the feed force.

It is an object of this invention to provide an improved feed control system for a drilling machine which renders the machine wholly safe, and yet sacrifices no feed force capacity.

It is another object of this invention to provide a feed control system comprising a machine support frame and means supporting said frame above ground level, said frame and means being movable therebetween, feed force supplying means for the machine drilling element, and means automatically responsive to relative movement between said frame and said supporting means to reduce the feed force.

It is yet another object of this invention to teach an orientation-sensing system for a drilling machine comprising a drilling machine support frame, means coupled to said frame for supporting said frame above ground level, wherein said frame and said supporting means together comprise at least two components disposed for relative movement therebetween in response to machine displacement, and means coupled to at least one of said components, and responsive to movement between said components, for signalling machine displacement.

A feature of this invention comprises the provisioning of at least one jack leg for slidable movement in the machine support frame, with the movement thereof actuating a valve effective for shunting the pressured fluid away from the drill feed motor.

Further objects and features of this invention will become more apparent by reference to the following description taken in conjunction with the accompanying figures, in which:

FIG. I, originally presented in my co-pending patent application, Ser. No. 63,524, is a combination schematic and pictorial illustration comprising an embodiment of the invention in which the schematic elements thereof depict the system fluid conduct and valving, and the pictorial portion represents a cross-sectional view of a frame member, mounting jack legs at the forward end of a drilling machine, and a portion of the drill string of such a machine; and

FIGS. 2-4 are added by way of this continuation-inpart.

FIG. 2 depicts an alternate, simpler embodiment of the invention, in combined schematic and pictorial illustration;

FIG. 3 a partial schematic, depicts yet a further embodiment of the invention in which one or more additional machine sub-systems are automatically, responsively controlled by the manifolding of such subsystems to the FIG. 2 embodiment; and

FIG. 4 presents, in vertical cross-section, structuring of the novelly-deployed pilot-operated relief valves and bleed button vent valves of FIGS. 2 and 3, and illustrates the functional cooperation therebetween.

With reference to FIG. 1, it is seen that frame member 10 carries jack legs 12 at either ends thereof slidably within apertures 14. What is shown here is only a portion of the forward end of a drilling machine which carries a drilling element 16 thereat, the element being operated, in a manner well known in the art, by the feed motor 18. Said motor 18 is supplied enabling energy, via an inlet port, by a pressurized-fluid supply line 20 through a feed-down" pressure line 22 which communicates with line 20. A feed-down return line 24 is in communication with an outlet port of the feed motor to return the pressurized fluid to a reservoir (not shown).

A shunt line 26 is connected, at either end thereof, in parallel with motor 18, with lines 22 and 24 and has interposed therein a shunt control valve 28. The shunt valve is actuated by pressured-fluid communicated thereto by excess feed pressure line 30. The other end of line 30 opens on a shuttle valve 32. Either ported ends of shuttle valve 32 are connected, through feed pressure sensor lines 34 and 36, to a supply tap line 38 which is tee-connected with the pressure fluid supply line 20.

Tap line 38 branches out into two spur lines 40 and 42 which supply pressured fluid to feed pressure sensor valves 44 and 44'. Each of these sensor valves has two operative sections which, for explanatory purposes, can be described as the conducting and vent sections. The conducting section 46 provides for communication of fluid directly therethrough from spur line 40 or 42 to lines 34 or 36. The vent section 48 is provided to communicate with a vent line 50 which opens on atmospheric pressure into a reservoir 52. Each of these sensor valves is restrained by a spring 54 to have vent section 48 thereof normally in operative position.

The sensor valves 44 and 44' are secured by mounting plates 56 torespective jack legs 12. Each valve has a plunger actuator 58 depending therefrom in adjacency to frame member 10 for engagement with the member if excessive feed force :raises the machine. Therefore, when an excessive feed. pressure or force is applied to drill element 16 the drilling machine will tilt about an arc Z. As shown in the figure, the righthand portion of this forward end of the drill machine is raised slightly. The tilting, occasioned by excessive feed force, allows the jack leg 12 on that side of the machine to move relative to member within the aperture 14. Jack leg 12 comprises a ground-borne reference element; it can move relative to aperture 14 only as far as the upper, annular shoulder 60 will accommodate. However, this slide of the jack leg 12 moves valve 44. As a result, the upper surface 62 of member 10 thereupon engages the plunger actuator 58 which, in turn, places conducting section 46 of valve 44 in operative position and supplies pressured fluid therethrough from lines 38, 40, and 34 to one side of the shuttle valve 32.

The shuttle valve 32 incorporates a valve shuttle element 64 which finds pressured fluid at one side thereof (i.e., the right-hand side, in the figure) and atmospheric pressure at the other side. Accordingly, the element 64 is displaced within the shuttle valve housing and permits the pressured fluid to communicate through line 30 to valve 28. The address of pressured fluid to valve 28 overcomes the resistance of spring 54' thereof and actuates valve 28. This latter valve has two operative sections, a shunt section 66 capable of communicating pressured fluid therethrough, and an open section 68 capable of interdicting a shunting of fluid through line 26. Spring 54' constrains valve 28 so that section 68 is normally in operative position. Therefore, pressured fluid admitted to the valve 28 places section 66thereof in operative position, and the pressured fluid supply for feed motor 18 is shunted across the motor, via line 26, and passed directly to the line 24. With the feed motor decelerated or halted the feed force is attenuated. Machine tilting ceases and, as the machine returns to leveled position, the jack leg 12 and frame member 10 exhibit relative movement again. Valve 44 removes from surface 62, and both valves 44 and 44 are returned to their normal disposition. Shuttle element 64 is returned to a medial position within the housing of valve 32, as it finds atmospheric pressure to both sides thereof. This has the result of cutting off a conduct of pressured fluid through lines 34 and 30 to valve 28. Valve 28, then, returns to its normal position and interdicts a communication of lines 22 and 24. Feed motor 18 can again supply full feed force to drilling element 16.

To insure that there is no sudden drop of the drilling machine onto the provisioned lower, shoulder 70 of the jack leg 12, the invention teaches the use of a pressured relief valve 72 in shunt line 26 for cooperation with valve 28. Valve 72 contemplates an adjustable device which can be set for a given pressure level to insure that the pressured fluid supply to the motor 18 does not drop to an atmospheric level.

In order to signal a dangerous condition, to alert the machine operator, the invention teaches an orientation-sensing system for the machine. Pressured-fluidactuated indicators 74 and 74a are operatively through-connected, via spur lines, with pressure sensor lines 34 and 36, respectively. COnsidering the operators view of the machine, from behind drilling element 16, indicator 74 signals a left-hand displacement of the machine, and indicator 74a signals a right-hand displacement. Of course, where the lateral discriminations are not desired or warranted, it would be sufficient, in an alternate embodiment of the invention; to connect an indicator 74 or 74a with line 30.

A drilling machine, such as that represented in part by drilling element 16, frame member 10, and jack legs 12, will at any time during a drilling operation have a given gross weight. It is mandatory for an efficient drilling operation to have a feed force capability which is at least as great, if not greater than the complementary weight of a readily displaceable portion of the machine. That is to say that for any operational condition, a drilling machine has a given weight which can be represented by the factor N." Now then, some portion of the machine, perhaps the front half or a left-hand or right-hand forward corner will have a weight of N-y" which is an exact complement to a feed force capability of the machine. Accordingly, if such feed force is applied to the drilling element that complementaryweight-portion of the machine will react and elevate from the ground. As explained herein, the invention teaches a system which is automatically operative, upon sensing this reactive displacement of a portion of the machine, to attenuate the feed force to prevent an over-tilting of the machine.

The inventive system shown and described incorporates two jack legs 12 slidably mounted in frame member 10, each jack 12 having a sensor'valve 44 or 44' mounted thereto. Such an arrangement is usable with almost any drilling machine having a forwardly mounted drilling element 16. However, it will be clear to those skilled in this art that only one slidable jack leg 12 and sensor valve (44 or 44) is necessary to practice the teaching of the invention. It remains only to arrange the system so that the one slidable jack leg and its associated sensor valve are disposed at the lightest portion of the machine. Actually, it is only necessary to lighten one corner of the machine, whereat the jack leg and valve arrangement is located, or alternatively, to weigh down the other three corners.

The shunt control valve 28 is supplied pressured fluid from the basic system feed-fluid supply, from line 20. This need not be so. An actuating supply of fluid for valve 28 can be independent of the line 20 supply. Of course, also, reservoirs 52 can be supplanted by one reservoir of common use for both lines 50 and line 24 as well, and reservoirs of any nature are unnecessary where the pressured fluid used in the system is a compressed gas such as air.

Jack legs 12 contemplate leveling jacks, known and practiced in the prior art, which comprise cylinder and piston arrangements for accommodating a leveling of the drilling machine. The cylinder-and-piston structuring is not shown as it is not germane to the instant invention. The invention, of course, can be practiced with extendable, leveling jack legs or with fixed-length, non-extendible jack legs.

The disclosed system is safe because all pertinent components thereof are almost continuously functioning, during site drilling operations; in contrast, safety features which are added-on to prior art feed control systems are supposed to function in danger situations only. Components of such standby safety features, given to very infrequent operation, are more likely to fail, or to be found inoperative, just at the time when they are needed.

The system is safe because the sliding movement of the jack legs 12 is made jam-free. Generous clearances between the 0.11. of the frame-confined portion of each leg 12 and the walls of the apertures 14 are provided.

The system is safe because all valves are of the spring-return type; the spring force required to reset the valves in normal disposition is only a small fraction of the force required to actuate the valves to the alternate operational disposition. This renders the valves more vulnerable to jamming in the reset positions which do not jeopardize safety.

The system is safe because leakage or line burst or valve burst will not jeopardize safety; small leakage will not effect functioning of the valves; large leakage or hose burst will not let the pressure build up.

The system can be made even more safe through the expedient of a parallel arrangement of identical sensor valves 44 or 44' on one or more jack legs 12, to provide further assurance of dependability, and through a parallel arrangement of identical shunt valves 28, for an additional margin of reliability.

To those skilled in the art here concerned, the de picted embodiment and its teaching will suggest other embodiments for practice of the invention. For instance, instead of a normally-closed pilot valve 28, a normally-open pilot valve could be employed with line 30 thereto through-connected with supply line 20 via a normally through-conducting sensor valve. In this, the supported weight of the machine will keep the normally closed pilot valve closed against spring-biasing, but will shunt the pressured feed fluid, from line 22 to line 24, in the absence of weight on the slidable jack leg 12 involved. When the leg 12 slides within aperture 14, and surface 62 engages actuator 58 the normally through-conducting sensor valve would be moved to vent position, the normally-open pilot valve would be displaced, via spring 54' to its open, shunting" position and attenuate the pressured feed fluid.

Sensor valves 44 and 44' could well be replaced by electrical switches operative of a solenoid-type valve put in place of valve 28, to practice the invention. Further sensor valves 44 and 44' could be supplanted by position switches, of mercury or other types, operative, in response to machine displacement, of a solenoidtype pilot valve. Accordingly, these and all other alternate embodiments are wholly within the spirit of my invention and find their teaching in my instant disclosure.

In the ensuing discussion, concerning FIGS. 2, 3, and 4, it is to be understood that components identified by index numbers which are similar to or the same as index numbers presented in FIG. 1, do, in fact, constitute similar or same components.

The alternate system embodiment of FIG. 2 incorporates the use of a pilot-operated relief valve 76, which by means of a vent line 78 proceeding therefrom and throughconnected with a manifold line 80, defines a shunt path for the pressure fluid. Bleed button vent valve 82 (or 82') opens in response to a tilting of the frame 10, i.e., a movement between frame and jack leg 12, to enable valve 76 to shunt the fluid. FIG. 4, and discussion herein in connection therewith, disclose how valve 76 effects the fluid shunting. A feed pump 84 supplies the pressured fluid to fluid supply line 20 and pressure line 22 for address thereof to a feed motor 18. A feed reversing and shut-off valve 86 is provided between lines 20 and 22, to reverse the feed (for retracting the drilling element 16) and for cutting off feed entirely.

When the plunger actuator 58 is displaced, it opens valve 82 (or 82') to present an atmospheric pressure to the pilot-operated relief valve 76. Thus, supply fluid line 20 is communicated, through valve 76 with the reservoir 52 via a line 75. Accordingly, the heretofore uninterrupted steady supply of feed pressure, for feed motor 18, is diminished (although sufficient pressure, necessary for effective drilling, is held on the feed motor by check valve 92), until such time as the drilling element 16 has negotitated a depth, in the surface being drilled, which is equivalent to Z/2 represented in the Figure.

The embodiment presented in FIG. 3 is similar to that of FIG. 2 except that other machine sub-systems can be automatically halted by additional relief valves. Such other machine systems have their enabling pressured fluid lines coupled to the manifold line 80 via such valves 76' and 76". For instance, this offers control of the pressurized fluid supply line 88, which may be for the tower raising sub-system, and pressurized fluid supply line which may be for the fast feed subsystem. Check valves 92 and 92" and 92" are provided to inhibit a communication of fluid through manifold line 80 into the other machine subsystems from the basic FIG. 2 system, to inhibit a communication of fluid from these other sub-systems to the FIG. 2 system, and to inhibit communication of fluid from one subsystem into another sub-system.

In FIG. 4 is depicted a cross-sectional view of the pilot-operated relief valve 76 (the same being typical of valves 76' and 76" as well) which enables operation of the embodiments of FIGS. 2 and 3 The valve 76 comprises a system pressure admittance port 94 and a fluid return port 96. The two ports would be in communication with each other except for the interposition of a valving spool. A spool chamber 98 opens on both ports 94 and 96 and slidably receives valving spool 100 therewithin. The spool carries a poppet 102, at one terminal end thereof, in a poppet cylinder 104. Cooperatively, the poppet 102 and cylinder 104 define a variable volume chamber 106 within. the valve body. A pilot passageway 108, formed in the body, opens at either ends on the chamber 106 and port 94. Thus, chamber 106 and poppet 102 are always under the influence of system pressure.

At the other end of the spool 100 there is disposed a spring retainer and bearing surface 110 which is slidably movable within an enlarged portion 112 of a pilot chamber 114. A spring 116 is enclosed in chamber 114 for urging the poppet 102 and spool 100 in a disposition (i.e., to the right, as viewed in FIG. 4) which will close off port 94 from port 96. A passageway 118 communicates, by way of an orifice 120 and a further pas sageway 122, the same all being formed within the valve body, with port 94. Therefore, chamber 114 and the spool end thereat are always under the influence of system pressure. A further passageway 124 is communicated directly with vent line 78 (and manifold line 80) for a through communication with the bleedbutton vent valve 82. Finally, a dog-leg passageway 126 formed within the valve body is interrupted by a standard-type, adjustable relief valve 128.

With particular reference to FIGS. 2 and 4, it will be noted that, when frame 10 engages plunger actuator 58 and causes the communication of lines 78 and 80 with the atmosphere, the pilot chamber 114 pressure is lowered. Accordingly, with system pressure being present at port 94 and being in communication with chamber 106, by way of passageway 108, the spool 100 is caused to move (toward the left, as viewed in FIG. 4), to communicate port 94 with port 96. Therefore, the pressured fluid, or some quantity of it which would be normally communicated to the feed motor 18 is dumped to the reservoir 52; the path is from port 96, line 75, and reservoir 52. Now, feed pressure addressed to the drilling element 16 is diminished until rotation of the drilling element 16 (by means not shown), in cooperation with the feed pressure checked by valve 92, causes a negotiation of a distance into the material being worked which will allow the frame to retract from shoulder 60. Thereupon, plunger actuator 58 is allowed to respond to the pressure of spring 54 again to close off valve 82. Pilot chamber 114 again returns to system pressure and spool 100 is returned to the position shown in FIG. 4 where ports 94 and 96 are closed off from each other.

Toward a more complete understanding of the invention and the operation of the enabling valve 76, it would be advisable, here, to present some arbitrary values. Therefore, for purposes of explanation, it will be considered that optimum system pressure for the drilling element feed is 3000 psi. With vent valve 82 (or 82) in its normally-closed position, spool 100 finds system pressure, the 3000 psi, at either ends thereof in chambers 106 and 114. Presumably, then, spool 100 might locate in any axially displaced position in chamber 98. It does not, however. Normally, spool 100 is disposed (as shown in FIG. 4) in closure of port 94 from port 96. This is so because of the displacement assistance provided by spring 116.

In spring 116 is contemplated an urging force of some 25 psi, approximately. This force, added to the system pressure of 3000 psi, in chamber 114, effects the afore-noted normal disposition of spool 100. When valve 82 (or 82') depressurizes chamber 114, to values below 2975 psi, the spool 100 yields to the superior pressure in chamber 106 to open port 94 to port 96.

Passageways 118 and 122, of course, communicate chamber 114 with port 94 and therefore with system pressure, but they do so only by way of the constricted orifice 120. In orifice 120 is contemplated a crosssection of approximately 0.040-inch diameter. This provisioning disallows the instantaneous tracking of system pressure, by chamber 114, which chamber 106 can exhibit. That is, chamber 106 rapidly reflects system pressure excursions, whereas chamber 114 because of orifice 120 can reflect such excursions only after a prescribed delay. Thus, a quick response of spool 100 is assured.

Chamber 114 will not sustain a system pressure rise above a pre-set value, and for the purposes of this discussion, the pre-set value, the given, optimum value, is

3000 psi. If chamber 114 pressure rises above 3000 psi,

valve 128, which is selectively set to open at that pressure, will vent the excess pressured fluid into port 96.

Should it happen that system pressure increases beyond the optimum value of 3000 psi, in the absence of an actuation of plunger actuator 58, the spool 100 will be displaced (toward the left) to dump some system pressure anyhow. This occurs as follows: with system pressure at port 94 and subsisting in chamber 106, and rising excessively, it is opposed only by the optimum pressure in pilot chamber 114 plus the 25 psi force of spring 116. Pilot chamber 114 as just noted, maintains only the optimum pressure, because relief valve 128 is set to relieve the excess pressure. Due to the differential in pressure disposed against poppet 102 and the piston-type opposite end of spool 100, i.e., 3025 psi, in chamber 114 and say 3028 psi, in chamber 106, the spool moves slidably (to the left) to broach a passageway between ports 94 and 96. The slightly excessive pressure of the system supply, accordingly, is dumped to the reservoir 52. The valve 76 constantly monitors and adjusts system pressure to insure that only the optimum supply is provided by way of lines 20 and 22 to the feed motor 18.

The advantages to be found in the embodiments comprised by FIGS. 2-4 are: a more rapid response of the feed control system to frame 10 displacement and- /or a rise in system pressure, and a more simplified system arrangement. Only two-way valves are used, and the deployment of a less-rapidly-responsive shuttle valve, shunt control valve, and the latters associated pressure relief valve (32, 28, and 72, respectively, FIG. 1) are dispensed with. Additionally, check valve 92 in line 20 holds pressure on motor 18 even if, for whatever reason, feed pump 84 becomes unloaded.

My automatic feed control systems, although inventively novel, in a practical way makes use of standard, commercially available components such as, relief valve 76, feed motor 18, and feed pump 84. Likewise, directional valve 86 and check valve 92 are standard, off-the-shelf types of elements. Customarily, in fact, valves such as valve 86 and 92 are available as an inte grated, packaged unit. For this reason, I have shown these two valves within a package-box/dashed line enclosure in FIG. 2.

While I have described my invention in connection with specific embodiments thereof it is to be clearly understood that this is done only by way of example and not as a limitation to the scope of my invention as set forth in the objects thereof and in the appended claims.

I claim:

1. An automatic feed control system for the drilling element of a drilling machine, comprising:

a drilling machine support frame;

means coupled to said frame for supporting said frame above ground level;

wherein said frame and said supporting means together comprise at least two components disposed for relative movement therebetween;

motor means, responsive to pressured fluid, for generating a feed force for application thereof to said drilling element;

means supplying pressured fluid to said motor; and

means coupled to at least one of said components,

and operatively connected to said fluid supplying means, and responsive to movement between said components for attenuating the supply of pressured fluid supplied to said motor, said attentuating means having means for shunting fluid away from said motor.

2. An automatic feed control system for the drilling element of a drilling machine, comprising:

a drilling machine support frame;

means coupled to said frame for supporting said frame above ground level;

wherein said frame and said supporting means together comprise at least two components disposed for relative movement therebetween;

means operative for developing a feed force for said drilling element; and

means coupled to at least one of said components,

and operatively connected to said force-developing means, automatically responsive to relative movement between said components to inhibit operation of said force-developing means; wherein said inhibit means includes means for attenuating the feed force developed by said force-developing means.

3. A system, according to claim 2, wherein said forcedeveloping means comprises:

a pressured-fluid-operated feed motor;

.a supply of pressured-fluid;

given means connecting said supply with said motor;

and

means for discharging fluid from said motor.

4. A system, according to claim 3, wherein:

said fluid discharging means comprises a fluid return line; and

said inhibit means includes means throughconnecting said supply with said return line.

5. A system, according to claim 4, wherein:

said throughconnecting means includes means for effecting pressured-fluid flow in shunting avoidance of said motor, and means for preventing a press ured-fluid flow in shunting avoidance of said motor.

6. A system, according to claim 5, wherein:

said shunting-flow-effecting means comprises a pressured-fluid shunt line opening at either opposite ends thereof on said supply and said return line.

7. A system, according to claim 6, wherein:

said shunting-flow-avoiding means comprises at least one pressured-fluid-actuable valve, interposed in said shunt line intermediate said opposite ends thereof, normally operative for interrupting said shunt line and operative, in response to pressured fluid communicated thereto, to accommodate fluid flow through said shunt line.

8. A system according to claim 7, wherein:

said inhibit means further include other means for communicating said supply with said valve, and for closing off communication of said supply with said valve.

9. A system, according to claim 7, wherein:

said shunting-flow-avoiding means further comprises a pressure-relief valve, interposed in said shunt line intermediate said fluid-actuable valve and one of said opposite ends, responsive to a predetermined fluid pressure to open said shunt line.

10. A system,according to claim 2, wherein:

said inhibit means further includes signalling means, also responsive to said relative movement, for signalling machine displacement. 11. An automatic feed control system for the drilling element of a drilling machine, comprising:

a drilling machine support frame;

means coupled to said frame for supporting said frame above ground level;

wherein said frame and said supporting means together comprise at least two components disposed for relative movement therebetween;

means operative for developing a feed force for said drilling element; and

means coupled to at least one of said components, and operatively connected to said force-developing means, automatically responsive to relative movement between said components to inhibit operation of said force-developing means; wherein said force-developing means comprises a pressuredfluid-operated feed motor,a supply of pressuredfluid,given means connecting said supply with said motor,and means for discharging fluid from said motor;

said fluid discharging means comprises a fluid return line; said inhibit means includes means throughconnecting said supply with said return line;

said throughconnecting means includes means for effecting pressured-fluid flow in. shunting avoidance of said motor, and means for preventing a pressured-fluid flow in shunting avoidance of said motor;

said shunting-flow-effecting means comprises a pressured-fluid shunt line opening at either opposite ends thereof on said supply and said return line;

said shunting-flow-avoiding means comprises at least one pressured-fluid-aetuable valve, interposed in said shunt line intermediate said opposite ends thereof, normally operative for interrupting said shunt line and operative, in response to pressured fluid communicated thereto, to accommodate fluid flow through said shunt line;

said inhibit means further include other means for communicating said supply with said valve, and for closing off communication of said supply with said valve; and

said other means comprise a pressured-fluid tap line having one of two ends thereof in throughcommunication with said supply, and an excess feed pressured-fluid line having one to two ends thereof in communication with said valve, and sensor means, coupled to the other ends of said tap line and said excess feed line, for sensing movement of said components and effecting fluid flow communication between said other ends automatically in response to such movement, and for automatically prohibiting such fluid flow communication between said other ends in an absence of such movement.

12.A system, according to claim 11, wherein:

said sensor means comprises a sensor valve configured for operative disposition in a plurality of operative positions and means operative in given ones of said positions to conduct fluid through said valve between said other ends of said tap line and said excess feed line, and to vent fluid from said sensor valve from one of said tap and said excess feed lines.

13. A system, according to claim 12, wherein:

said sensor valve includes means effective for restraining said sensor valve in a given operative position which accommodates the venting of fluid from said sensor valve and means operative in another of said positions which accommodates the conduct of fluid through said sensor valve between said other ends of said tap and excess feed lines.

14. A system, according to claim 13, wherein:

said supporting means comprises a jack leg;

said sensor valve is extendably mounted to said jack leg;

said actuator means comprises a plunger-actuator depending from said sensor valve; and

said actuator means is disposed in adjacency to a surface of said frame.

15. A system, according to claim 14, wherein:

said frame has an aperture of a given length formed therein; said jack leg has a shank of uniform cross-section and of slightly greater length than said given length, which shank is terminated at either ends thereof in outwardly extending annular shoulders; and said shank is slidably disposed within said aperture. 16. A system, according to claim 14, wherein: said plunger-actuator closes upon and engages said frame surface, with a given relative movement between said jack leg and said frame, and is actuated, in response to frame engagement, to dispose said sensor valve in said another position. 17. A system, according to claim 14, wherein: said plunger-actuator removes from said frame surface, with a given relative movement between said jack leg and said frame, and is actuatored, in response to frame disengagement, to dispose said sensor valve in said given operative position. 18. An automatic feed control system for the drilling element of a drilling machine, comprising:

means for generating a feed force, for application thereof to said element, sufficient to displace said machine in reaction to said force; and means intercoupling said force-generating means and said machine responsive to machine displacement automatically operative to attenuate feed force generation by said generating means. 19. A system, according to claim 18, further including:

a drilling machine support frame; and means coupled to said frame for supporting said frame above ground level; wherein said frame and said supporting means together comprise at least two components disposed for relative movement therebetween in response to machine displacement; and wherein said inhibit means comprises movement-sensor means coupled to said one of said components in proximity to the other of said components to sense relative movement therebetween. 20. A system, according to claim 19, wherein: said inhibit means further includes signalling means, also responsive to said relative movement, for signalling machine displacement. 21. An automatic feed control system, for the drilling element of a drilling machine having a groundsupported frame, comprising:

first means, coupled to said drilling element, operative for supplying pressured fluid to said drilling element to effect feed thereof into the ground; second means, coupled both to said frame and to said fluid supplying means, automatically responsive to a displacement of said frame relative to the ground to inhibit fluid supplying operation of said first means; wherein said first means comprises a feed-force generating fluid motor; a supply of pressured fluid, including a fluid reservoir and a first fluid supply line interconnecting and communicating said supply and said motor; and

said second means comprises first normally-closed valving means interconnecting said reservoir with said first fluid supply line at a point in said first fluid supply line intermediate said supply and said motor, and vent line means interconnecting said reservoir with said first valving means, including second normally-closed valving means operative for connecting both said vent line means and said first valving means with the atmosphere; and

said first valving means has means responsive to a communication of said second valving means with the atmosphere for opening said first valving means to effect a shunting discharge of pressure fluid therethrough from said supply line to said reservoir.

22. An automatic feed control system, according to claim 21, wherein:

said second means comprises means borne by the ground, and stable relative thereto during drilling operations of the machine, for defining thereof a ground-reference element;

said frame is disposed for movement relative to said ground-reference element.

23. An automatic feed control system, according to claim 22, wherein:

said valving means comprises a vent valve, carried by said ground-reference element, having an extending, operating actuator;

said actuator being disposed for operative engagement thereof by said frame, with movement of said frame relative to said ground-reference element, to cause said actuator operatively to open said vent valve to the atmosphere.

24. An automatic feed control system, according to claim 21, wherein:

said vent line means comprises a manifold line; and

further including at least a second fluid supply line, for powering a fluid-enabled machine sub-system; means throughconnecting said second fluid supply line with said manifold line, including third normally-closed valving means further interconnecting said reservoir with said second fluid supply line;

and said third valving means having means responsive to a communication of said second valving means with the atmosphere for opening said third valving means to effect a shunting discharge of pressure fluid therethrough from said second supply line to said reservoir.

25. An automatic feed control system, for the drilling element of a drilling machine having a groundsupported frame, comprising:

first means, coupled to said drilling element, operative for supplying pressured fluid to said drilling element to effect feed thereof into the ground; second means, coupled both to said frame and to said fluid supplying means, automatically responsive to a displacement of said frame relative to the ground to attenuate fluid supplying operation of said first means. 

1. An automatic feed control system for the drilling element of a drilling machine, comprising: a drilling machine support frame; means coupled to said frame for supporting said frame above ground level; wherein said frame and said supporting means together comprise at least two components disposed for relative movement therebetween; motor means, responsive to pressured fluid, for generating a feed force for application thereof to said drilling element; means supplying pressured fluid to said motor; and means coupled to at least one of said components, and operatively connected to said fluid supplying means, and responsive to movement between said components for attenuating the supply of pressured fluid supplied to said motor, said attentuating means having means for shunting fluid away from said motor.
 2. An automatic feed control system for the drilling element of a drilling machine, comprising: a drilling machine support frame; means coupled to said frame for supporting said frame above ground level; wherein said frame and said supporting means together comprise at least two components disposed for relative movement therebetween; means operative for developing a feed force for said drilling element; and means coupled to at least one of said components, and operatively connected to said force-developing means, automatically responsive to relative movement between said components to inhibit operation of said force-developing means; wherein said inhibit means includes means for attenuating the feed force developed by said force-developing means.
 3. A system, according to claim 2, wherein said force-developing means comprises: a pressured-fluid-operated feed motor; a supply of pressured-fluid; given means connecting said supply with said motor; and means for discharging fluid from said motor.
 4. A system, according to claim 3, wherein: said fluid discharging means comprises a fluid return line; and said inhibit means includes means throughconnecting said supply with said return line.
 5. A system, according to claim 4, wherein: said throughconnecting means includes means for effecting pressured-fluid flow in shunting avoidance of said motor, and means for preventing a pressured-fluid flow in shunting avoidance of said motor.
 6. A system, according to claim 5, wherein: said shunting-flow-effecting means comprises a pressured-fluid shunt line opening at either opposite ends thereof on said supply and said return line.
 7. A system, according to claim 6, wherein: said shunting-flow-avoiding means comprises at least one pressured-fluid-actuable valve, interposed in said shunt line intermediate said opposite ends thereof, normally operative for interrupting said shunt line and operative, in response to pressured fluid communicated thereto, to accommodate fluid flow through said shunt line.
 8. A system according to claim 7, wherein: said inhibit means further include other means for communicating said supply with said valve, and for closing off communication of said supply with said valve.
 9. A system, according to claim 7, wherein: said shunting-flow-avoiding means further comprises a pressure-relief valve, interposed in said shunt line intermediate said fluid-actuable valve and one of said opposite ends, responsive to a predetermined fluid pressure to open said shunt line.
 10. A system,according to claim 2, wherein: said inhibit means further includes signalling means, also responsive to said relative movement, for signalling machine displacement.
 11. An automatic feed control system for the drilling element of a drilling machine, comprising: a drilling machine support frame; means coupled to said frame for supporting said frame above ground level; wherein said frame and said supporting means together comprise at least two components disposed for relative movement therebetween; means operative for developing a feed force for said drilling element; and means coupled to at least one of said components, and operatively connected to said force-developing means, automatically responsive to relative movement between said components to inhibit operation of said force-developing means; wherein said force-developing means comprises a pressured-fluiD-operated feed motor,a supply of pressured-fluid,given means connecting said supply with said motor,and means for discharging fluid from said motor; said fluid discharging means comprises a fluid return line; said inhibit means includes means throughconnecting said supply with said return line; said throughconnecting means includes means for effecting pressured-fluid flow in shunting avoidance of said motor, and means for preventing a pressured-fluid flow in shunting avoidance of said motor; said shunting-flow-effecting means comprises a pressured-fluid shunt line opening at either opposite ends thereof on said supply and said return line; said shunting-flow-avoiding means comprises at least one pressured-fluid-actuable valve, interposed in said shunt line intermediate said opposite ends thereof, normally operative for interrupting said shunt line and operative, in response to pressured fluid communicated thereto, to accommodate fluid flow through said shunt line; said inhibit means further include other means for communicating said supply with said valve, and for closing off communication of said supply with said valve; and said other means comprise a pressured-fluid tap line having one of two ends thereof in throughcommunication with said supply, and an excess feed pressured-fluid line having one to two ends thereof in communication with said valve, and sensor means, coupled to the other ends of said tap line and said excess feed line, for sensing movement of said components and effecting fluid flow communication between said other ends automatically in response to such movement, and for automatically prohibiting such fluid flow communication between said other ends in an absence of such movement.
 12. A system, according to claim 11, wherein: said sensor means comprises a sensor valve configured for operative disposition in a plurality of operative positions and means operative in given ones of said positions to conduct fluid through said valve between said other ends of said tap line and said excess feed line, and to vent fluid from said sensor valve from one of said tap and said excess feed lines.
 13. A system, according to claim 12, wherein: said sensor valve includes means effective for restraining said sensor valve in a given operative position which accommodates the venting of fluid from said sensor valve and means operative in another of said positions which accommodates the conduct of fluid through said sensor valve between said other ends of said tap and excess feed lines.
 14. A system, according to claim 13, wherein: said supporting means comprises a jack leg; said sensor valve is extendably mounted to said jack leg; said actuator means comprises a plunger-actuator depending from said sensor valve; and said actuator means is disposed in adjacency to a surface of said frame.
 15. A system, according to claim 14, wherein: said frame has an aperture of a given length formed therein; said jack leg has a shank of uniform cross-section and of slightly greater length than said given length, which shank is terminated at either ends thereof in outwardly extending annular shoulders; and said shank is slidably disposed within said aperture.
 16. A system, according to claim 14, wherein: said plunger-actuator closes upon and engages said frame surface, with a given relative movement between said jack leg and said frame, and is actuated, in response to frame engagement, to dispose said sensor valve in said another position.
 17. A system, according to claim 14, wherein: said plunger-actuator removes from said frame surface, with a given relative movement between said jack leg and said frame, and is actuatored, in response to frame disengagement, to dispose said sensor valve in said given operative position.
 18. An automatic feed control system for the drilling element of a drilling machine, comprising: means for generating a feed force, for application thereof tO said element, sufficient to displace said machine in reaction to said force; and means intercoupling said force-generating means and said machine responsive to machine displacement automatically operative to attenuate feed force generation by said generating means.
 19. A system, according to claim 18, further including: a drilling machine support frame; and means coupled to said frame for supporting said frame above ground level; wherein said frame and said supporting means together comprise at least two components disposed for relative movement therebetween in response to machine displacement; and wherein said inhibit means comprises movement-sensor means coupled to said one of said components in proximity to the other of said components to sense relative movement therebetween.
 20. A system, according to claim 19, wherein: said inhibit means further includes signalling means, also responsive to said relative movement, for signalling machine displacement.
 21. An automatic feed control system, for the drilling element of a drilling machine having a ground-supported frame, comprising: first means, coupled to said drilling element, operative for supplying pressured fluid to said drilling element to effect feed thereof into the ground; second means, coupled both to said frame and to said fluid supplying means, automatically responsive to a displacement of said frame relative to the ground to inhibit fluid supplying operation of said first means; wherein said first means comprises a feed-force generating fluid motor; a supply of pressured fluid, including a fluid reservoir and a first fluid supply line interconnecting and communicating said supply and said motor; and said second means comprises first normally-closed valving means interconnecting said reservoir with said first fluid supply line at a point in said first fluid supply line intermediate said supply and said motor, and vent line means interconnecting said reservoir with said first valving means, including second normally-closed valving means operative for connecting both said vent line means and said first valving means with the atmosphere; and said first valving means has means responsive to a communication of said second valving means with the atmosphere for opening said first valving means to effect a shunting discharge of pressure fluid therethrough from said supply line to said reservoir.
 22. An automatic feed control system, according to claim 21, wherein: said second means comprises means borne by the ground, and stable relative thereto during drilling operations of the machine, for defining thereof a ground-reference element; said frame is disposed for movement relative to said ground-reference element.
 23. An automatic feed control system, according to claim 22, wherein: said valving means comprises a vent valve, carried by said ground-reference element, having an extending, operating actuator; said actuator being disposed for operative engagement thereof by said frame, with movement of said frame relative to said ground-reference element, to cause said actuator operatively to open said vent valve to the atmosphere.
 24. An automatic feed control system, according to claim 21, wherein: said vent line means comprises a manifold line; and further including at least a second fluid supply line, for powering a fluid-enabled machine sub-system; means throughconnecting said second fluid supply line with said manifold line, including third normally-closed valving means further interconnecting said reservoir with said second fluid supply line; and said third valving means having means responsive to a communication of said second valving means with the atmosphere for opening said third valving means to effect a shunting discharge of pressure fluid therethrough from said second supply line to said reservoir.
 25. An automatic feed control system, for the drilling element of a drilling Machine having a ground-supported frame, comprising: first means, coupled to said drilling element, operative for supplying pressured fluid to said drilling element to effect feed thereof into the ground; second means, coupled both to said frame and to said fluid supplying means, automatically responsive to a displacement of said frame relative to the ground to attenuate fluid supplying operation of said first means. 